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Protein powder 101

Protein powder has long been touted as the go-to supplement for muscle growth, athletic performance, and weight loss. But what is protein powder, how much should you take, and are there any risks associated with it? Here’s everything you need to know about protein powder.

Let’s face it: protein shakes are hard to beat if you’re looking to build muscle, enhance recovery, or lose weight, and need a quick and convenient source of nutrition. Studies have long shown that protein plays a major role in building lean muscle mass, improving strength, and promoting tissue repair.
However, protein powder varies widely in content, quality, and effectiveness. From nutrition content to potential risks, here’s what science has to say about protein powder.

What does protein do?

Protein is an essential macronutrient composed of 20 different amino acids, nine of which must be obtained from the diet because the body can’t produce them on its own. Amino acids are considered the primary building blocks of your body because they are found in muscles, tendons, bone, skin, hormones, tissue, enzymes, red blood cells, and more [1].  
Dietary protein provides the amino acids your body needs to build and repair muscles, heal wounds and injuries, synthesize hormones and enzymes, and even store and carry oxygen throughout the body. Good protein sources include eggs, dairy, lean meat, poultry, fish, beans, lentils, soybeans, tofu, and supplements (such as protein powder) or protein-fortified foods.

What is protein powder?

Protein powder is a powdered form of protein that comes from milk (casein or whey), egg white powder, or plant sources (soy, pea, rice, pumpkin seed and hemp). Protein powders often contain other ingredients–like artificial sweeteners and/or flavorings, thickening agents, vitamins and minerals, and other functional ingredients–and vary in protein content depending on the type used. For instance, whey protein offers 25 grams of protein/serving, whereas pea protein contains 15 grams of protein/serving [2,3]. 
Learn more about the best forms of protein powder for men and women.
A man and a woman drinking protein shakes

How much protein powder should you consume per day?

How much protein you need per day varies with age and can increase significantly with physical activity, injury, and/or illness. While you can get adequate amounts of protein through diet, protein powder can help bridge the gap for any deficiencies. 
The Dietary Reference Intake (DRI) for protein for adults is as follows:
  • Men and women: 0.8 g protein/kg of body weight/day [4
  • Over 65 years old: 1 to 1.2 g protein/kg of body weight/day [5
Protein recommendations for athletes and highly active men and women range from 1.2-2.0 g/kg of body weight/day, depending on training needs and goals [6,7,8]. These numbers will vary depending on your activity level, age, and other needs, so talk with a dietitian or your healthcare provider to see what is right for you.
Athletes, weight lifters, older adults, active men and women, vegetarians/vegans, and individuals with a chronic illness may find it challenging to meet their protein goals from food alone, so they may benefit from including protein powder in their diet.

Protein powder benefits

Protein (and protein powders) offer a wide range of health benefits, including increased exercise performance, reduced muscle damage, and faster tissue repair [9,10,11]. In addition to recovery, here’s how you can use protein powder for weight loss and muscle gain. 

Weight management. 

Evidence suggests that high protein diets (consisting of 25-30% of your daily caloric intake from foods and supplements) will boost your metabolic rate and aid with weight loss [12,13].

Muscle gain. 

If you’re looking for an extra boost in the gym, you may want to reach for that protein shake. Studies have found that those who consumed additional protein after weight lifting showed increased muscle size and strength compared to those who didn’t [14].

How long does it take for protein powder to work?

Research shows that consuming protein (of any form) up to two hours after your workout may help to build muscle mass, and promote recovery, especially when paired with carbohydrate [15]. It’s also been found that taking a protein shake on an empty stomach before or immediately after a workout may benefit muscle protein synthesis, which is especially important for athletic performance [4,16]. 
While timing your protein intake may prove beneficial for athletes, researchers agree that it’s more important for non-athletic people to focus on getting enough quality protein each day as this will benefit overall health [17,18].

How long is protein powder good for?

When stored under normal conditions, whey protein powder is good for 9-18 months, but the shelf life could be extended up to two years depending on the additives used from manufacturers [19]. Plant-based protein powders can last up to two years since they don’t contain milk or dairy products.
While this timeline is a general rule of thumb, it’s not a substitute for examining how your protein powder looks or smells. If it has a rancid smell, bitter taste, changes in color, or is clumping, then it may have gone bad, regardless of the package date [19].
Three protein shakes next to blue dumbbells on a gray background

What to mix protein powder with?

You can mix most protein powders with water, milk, or plant-based milk alternatives to enjoy as a quick pre- or post-workout drink. However, if you want to up the nutritional value, blend your protein powder up with some spinach, berries, avocado, and chia seeds for added omega-3 fatty acids, fiber, vitamins, and minerals.

Potential risks of protein powder

Despite the benefits, there are potential risks associated with protein powder.
  • Considered to be a supplement. Unlike food, supplement regulation is largely in the hands of the manufacturer, and FDA approval is only required when the product contains a new ingredient. Additionally, the FDA is responsible for taking action against adulterated or misbranded supplement products. Since protein powders are considered to be a supplement, they aren’t regulated, which is why it’s important to choose a product that has been third-party tested to ensure that what you see on the nutrition label is what you get.
  • Possible digestive upset. Excessive protein consumption may cause digestive problems, such as nausea, bloating, cramping, flatulence, and diarrhea. 
  • May contain added sugars. While some protein powders may only have a few ingredients, others could have as much as 23 g of added sugar/scoop (which is almost the recommended daily limit for added sugar) [20]. Studies show that consuming excessive amounts of refined sugar can lead to a myriad of health issues, such as increased risk of heart disease, cancer, weight gain, and type 2 diabetes, so it’s important to look at the protein powder labels and opt for the one with the least amount of added sugar [21]. 
  • Possible contaminants. Protein powders are notorious for containing contaminants such as BPA, lead and other heavy metals, such as arsenic, cadmium, and mercury. One study found that 40% of tested protein powder products had elevated levels of arsenic, cadmium, mercury, and lead, with another report showing that 70% and 74% of their test products contained measurable levels of lead and cadmium, respectively [22,23]. While this sounds concerning, science may say otherwise–despite the fact that heavy metals are found in protein powders, studies have shown that the amount present in these products don’t pose an increased risk to your health [22]. One way to get around this is to choose protein powders that have been third-party tested to reduce your exposure.
  • Be aware of artificial sweeteners. Manufacturers often use artificial sweeteners in place of added sugars, and while this may seem like a better alternative, science says otherwise. Emerging research has found that artificial sweeteners (like aspartame, acesulfame-K, and sucralose) are correlated with an increased risk of cancer, so be sure to check the labels before purchasing protein powder [24].
A scoop of protein powder and a protein shake bottle

Personalized protein powder

Personalized protein powder is a custom blend of protein designed to support your unique health and fitness goals and align with your dietary preferences. Think of it as a supplement and protein powder in one scoop, specifically designed for you. Since we all have different nutritional needs and goals, you need a protein powder that will work for you, not against you. A personalized protein powder will dictate the right amount of protein, specify ingredients (plant vs. whey), and include functional additives (like probiotics and ashwagandha), all of which are tailored to your body’s needs and can help drive outcomes.
While personalized protein powders are usually more expensive than their generic counterparts, they can be an effective way to get the right blend of protein for your specific needs.


Fitness professionals and health enthusiasts alike have long been singing the praises of protein powder–and for good reason. Studies show that protein plays a major role in maintaining lean muscle mass, weight maintenance (or weight loss), improved strength, and tissue repair, and while you can get adequate amounts of this macronutrient through dietary sources, protein powder can be a quick and easy way to get it in. While there are potential risks associated with protein powder (such as added sugars, digestive issues and possible contaminants), the benefits may outweigh the negative if you choose a product that has been third-party tested.
Disclaimer: The text, images, videos, and other media on this page are provided for informational purposes only and are not intended to treat, diagnose or replace personalized medical care.

Key takeaways

  • Protein powder is a powdered form of protein that either comes from milk (casein or whey) or plant sources (soy, pea, rice, or hemp).
  • Protein (and protein powders) offer a wide range of health benefits, including increased exercise performance, reduced muscle damage, faster tissue repair, weight maintenance (or weight loss) and muscle gain [9,10,11].
  • There is no right or wrong time to take protein powder for it to be effective, but some evidence suggests that certain times may be more beneficial than others depending on your goals. 
  • Potential risks associated with protein powders include added sugars, digestive issues, and possible contaminants.
  • Since protein powders are considered to be a supplement, they aren’t regulated, which is why it’s important to choose a product that has been third-party tested to ensure that what you see on the nutrition label is what you get.


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